Buoyed by optimism about the recently released iPhone X, Apple added 0.82 percent and ended with a market capitalization of $905 billion, its highest ever.

More broadly, investors remained nervous about the potential outcome of the Republican plan unveiled last week that would cut corporate taxes while eliminating a range of popular tax breaks. The bill is expected to face strong opposition from interest groups.

Republicans have yet to score a major legislative win since Trump took office in January, even though the party controls both chambers of Congress as well as the White House.

“It’s a complicated, messy affair to get a tax bill passed,” said Tim Dreiling, Regional investment Director for U.S. Bank Private Wealth Management, with $150 billion in assets under management.

“There is going to be some give and take before we get a final tax package to be voted on.”

The S&P 500 has risen about 21 percent since the election of President Donald Trump a year ago, partly on the back of his promises to cut taxes and other business-friendly measures.

A trader works on the floor of the New York Stock Exchange (NYSE) shortly after the announcement that the U.S. Federal Reserve will hike interest rates in New York, U.S., December 14, 2016. REUTERS/Lucas Jackson/Files

The three major indexes closed at record highs.

The Dow Jones Industrial Average .DJI edged up 0.03 percent to end at 23,563.36, while the S&P 500 .SPX gained 0.14 percent to 2,594.38.